Tahere Taghizade-Firozjaee; Sina Khoshnevisan; Seyedeh Fatemeh Khakzad; Reza Sheikh; Samad Emamgholizadeh
Abstract
This study provides a comprehensive seasonal assessment of the Gorganrood River's water quality in Iran using the IRWQIsc and the NSFWQI, integrated with the novel OPLO-POCOD decision-making model. Water samples from four stations were analyzed for eleven (IRWQIsc) and nine (NSFWQI) physicochemical ...
Read More
This study provides a comprehensive seasonal assessment of the Gorganrood River's water quality in Iran using the IRWQIsc and the NSFWQI, integrated with the novel OPLO-POCOD decision-making model. Water samples from four stations were analyzed for eleven (IRWQIsc) and nine (NSFWQI) physicochemical and biological parameters across all four seasons of 2023. The results revealed significant temporal variations, with the highest water quality observed at the upstream Soosra station in summer and Noudeh in winter, generally categorized as "moderate" to "relatively bad." However, most station-season combinations indicated "bad" to "relatively bad" water quality. Spatially, upstream sites consistently showed better quality than downstream stations, with Araz Koseh and Ghzaghli exhibiting the lowest scores, likely due to accumulated pollution from urban, agricultural, and industrial sources. Shannon entropy analysis identified turbidity, total solids (TS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD) as key factors influencing water quality. The OPLO-POCOD method's rankings aligned well with the conventional indices, validating this hybrid approach for detailed water quality evaluation. The findings highlight the urgent need for continuous monitoring and targeted management strategies, including improved wastewater treatment, runoff control, and riparian protection, to preserve the Gorganrood River's ecological health and water supply functions.
Hasan Aminirad; Ozeair Abessi; Farshad Golbabaei Kootenaei; Mohammad Amin Mirrezaei; Tahereh Taghizadeh; Pooneh Saeidi; Gholamreza Darvishi
Abstract
Rivers are one of the primary water resources for agricultural, drinking, industrial and environmental applications; thus, assessment of the river water quality has a great significance. This study aims to evaluate the self-purification capacity of the Haraz river and identify critical areas ...
Read More
Rivers are one of the primary water resources for agricultural, drinking, industrial and environmental applications; thus, assessment of the river water quality has a great significance. This study aims to evaluate the self-purification capacity of the Haraz river and identify critical areas with the lack of dissolved oxygen along the river. Also, the QUAL2K model, IRWQI and NSFWQI indexes were applied for the determination of water quality. In this study, primary pollutant sources including urban areas, industrial centers, farmlands and multiple cold-water fish farms that their water usage and discharge have severe consequences on the quality and quantity of the river's stream were identified and located. This model was built and calibrated for four seasons with data from six sampling stations of Haraz river. Based on this study, upstream of Haraz river has adequate self-purification capacity in comparison to its midstream and downstream, especially in the Amol city area, lack of dissolved oxygen was observed and self-purification capacity considerably reduced. The critical areas of Haraz river in spring and winter seasons are downstream and the estuary region, while in summer and autumn, critical areas are increased in Amol city. In general, as the elevation decreases, the water quality decreases. Only in upstream areas (near the Poloor village and before the Chelav station), water quality is in the average condition, but near the Caspian sea, the condition of Haraz river is worrying due to the existence of contamination sources.
